In vanlife some people have built recirculating showers that use just a few gallons of water running in a loop. They run it through particle and UV filters whic

In vanlife some people have built recirculating showers that use just a few gallons of water running in a loop. They run it through particle and UV filters which supposedly clean the bad stuff out, but I haven't seen any scientific studies done on how effective that is. I imagine it is no worse than a bath, other than you are potentially putting bacteria into the air and hence your lungs. The idea sounds interesting though, as showers (even low flow) use a lot of water and heat, which typically just goes down the drain.